The name of Aryabhatta emerged during this period. He became famous as a mathematician and astronomer. He wrote a book is Sanskrit known as the Aryabhatiyam. He stated that day and night were caused by the rotation of the earth on its axis, even though it seems as if the sun is rising and setting everybody. He developed a scientific explanation for eclipses as well. He also found a way of calculating the circumference of a circle, which is nearly as accurate as the formula we use today.